1.0.47.20: don't handle errors during compile-time-too processing

1.0.47.20: don't handle errors during compile-time-too processing

  Essentially reverts 1.0.33.13.

  Handling compile-time-too errors has a nasty tendency to swallow
  things package conflict errors from DEFPACKAGE forms, and dump them
  into fasls without allowing the user to handle them reasonably.

  While it may be that there are specific cases which should/could be
  handled and converted into compiler-errors, I believe they are the
  the minority. For a moment I considered simply not handling
  conditions which have restarts associated with them, but it seems to
  me that

    (eval-when (:compile-toplevel) (error "oops"))

  is most often a signal that something is seriously wrong, and
  compiling rest of the file is a waste of time and only obfuscates
  the real problem.